From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: EuroSec'11 Presentation Date: Wed, 13 Apr 2011 11:04:05 -0700 Message-ID: References: <20110411.001930.73371943.k.suzaki@aist.go.jp> <4DA31DDF.7060605@codemonkey.ws> <20110412.004641.91284108.k.suzaki@aist.go.jp> <4DA322D9.40304@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Kuniyasu Suzaki , anthony@codemonkey.ws, stefanha@gmail.com, kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mga03.intel.com ([143.182.124.21]:6123 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753554Ab1DMSE0 (ORCPT ); Wed, 13 Apr 2011 14:04:26 -0400 In-Reply-To: <4DA322D9.40304@redhat.com> (Avi Kivity's message of "Mon, 11 Apr 2011 18:48:41 +0300") Sender: kvm-owner@vger.kernel.org List-ID: Avi Kivity writes: > > With EPT or NPT you cannot detect if a page is read only. Why not? You can always walk the page tables manually again. > Furthermore, at least Linux (without highmem) maps all of memory with > a read/write mapping in addition to the per-process mapping, so no > page is read-only. Even with 32bit highmem most memory will be eventually mapped writable by kmap when. There's currently no concept of a ro-kmap. However I suspect it wouldn't be too hard to add one. -Andi -- ak@linux.intel.com -- Speaking for myself only